This invention relates generally to apparatus for dispensing liquid and more particularly relates to apparatus for dispensing pressurized liquid with improved liquid retention for preventing unwanted liquid dispensing.
Numerous apparatus for dispensing liquid are known to the prior art. For example, and not by way of limitation, the typical blow-fill-seal machine known to the prior art includes apparatus for dispensing liquid into a partially formed plastic container, produced by blow molding, after which the container is sealed to provide what is typically referred to in the art as a pre-filled container. Such apparatus for dispensing liquid typically includes a single, hollow, elongated, cylindrical tube through which the liquid is dispensed into the partially formed plastic container; the single, hollow, elongated, cylindrical tube is typically referred to in the art as a fill needle. Upon cessation of such liquid dispensing, typically produced by valve action, liquid is retained in the fill needle by capillarity caused by surface tension between the retained liquid and the internal wall of the fill needle. Since the blow-fill-seal machine includes moving parts, vibration can be experienced which is sufficient to disrupt or overcome the surface tension between the retained liquid and the internal wall of the fill-needle causing highly undesirable over filling of the container and/or mess or liquid spillage which can be sufficient to require operation of the blow-fill-seal machine to be stopped for cleaning. Continuous operation of the blow-fill-seal machine is highly desirable for increased productivity with attendant production cost decrease while such machine stoppage is highly undesirable due to reduced productivity with attendant increase of production cost.
Accordingly, there is a need in the art for apparatus for dispensing liquid with improved liquid retention which, by way of example and not by way of limitation, is particularly useful with the above-noted blow-fill-seal machines.